Washington: Rare mutations that shut down a single gene called NPC1L1 are linked to lower cholesterol levels and a 50 percent reduction in the risk of heart attack, says an Indian-origin cardiologist.

People with one inactive copy of NPC1L1 appeared to be protected against high LDL cholesterol - the so-called “bad” cholesterol - and coronary heart disease, a narrowing of the heart's arteries that can lead to heart attacks, the findings showed.

"Protective mutations like the one we have just identified for heart disease are a treasure trove for understanding human biology," said senior author Sekar Kathiresan, director of preventive cardiology at Massachusetts General Hospital.

"They can teach us about the underlying causes of disease and point to important drug targets," Kathiresan noted.

For the study, the researchers pooled data from about 113,000 people.

The investigators found that people with only one working copy of the gene had LDL cholesterol levels an average of 12 milligrams per deciliter lower than the wider population of people with two working copies of the gene.

"This analysis demonstrates that human genetics can guide us in terms of thinking about appropriate genes to target for clinical therapy," said first author Nathan Stitziel, a cardiologist at Washington University School of Medicine.

The individuals with the rare gene mutations did not appear to differ from the larger population in any other way, including in measures of blood pressure, body mass index and rates of diabetes.